Folding trailer

ABSTRACT

A trailer has a three-section flat bed in which the front and rear sections fold onto the middle section. The trailer has an airbag suspension system and one wheel on each side. When the airbags are deflated, the entire flat bed forms a ramp for loading and unloading. When the airbags are deflated and the flat bed is folded, the trailer can be stored vertically while resting on its wheels.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. application Ser. No. 14/645,664, Mar. 12, 2015, now pending, which application is a continuation in part of U.S. application Ser. No. 14/146,829, Jan. 3, 2014, which application claims the benefit of U.S. Provisional Application Ser. No. 61/749,522, Jan. 7, 2013.

FIELD OF THE INVENTION

This invention relates to land vehicles. More particularly, this invention relates to trailers.

BACKGROUND OF THE INVENTION

A trailer is an unpowered wheeled vehicle that is used for hauling cargo. The surface upon which the cargo rests is most commonly known as a bed, but is also known as a deck or a platform. Trailers having an uncovered flat bed are used to transport motorcycles, lawn tractors, all terrain vehicles, watercraft, and other personal cargo. Flat bed trailers typically contain tongues with couplers that attach to a trailer hitch mounted on the back end of an automobile or truck.

Flat bed trailers typically include a suspension system to dampen the movement of the bed as the wheels pass over uneven surfaces. Suspension systems typically include coil springs, shock absorbers, or struts that are mounted between the components that support the wheels and the bed. Suspension systems containing airbags have also been disclosed. For example, De Roshia, U.S. Pat. No. 3,102,738, Sep. 3, 1963; Gladish, U.S. Pat. No. 4,335,901, Jun. 22, 1982; Smith et al., U.S. Pat. No. 4,934,733, Jun. 19, 1990; Smith, U.S. Pat. No. 5,275,430, Jan. 4, 1994; Nowell et al., U.S. Pat. No. 5,560,639, Oct. 1, 1996; Overby et al., U.S. Pat. No. 5,951,032, Sep. 14, 1999; Wayrynen, U.S. Pat. No. 7,281,728, Oct. 16, 2007; Sherwood, U.S. Pat. No. 7,537,219, May 26, 2009; and Fankhauser et al., U.S. Pat. Appln. Publn. No. 2010/0289250, Nov. 18, 2010, disclose trailers having air bag suspension systems.

Flat bed trailers are relatively bulky and take up considerable storage space when not in use, when on display at retail stores, and when shipped from the point of manufacture to the point of sale. To reduce the storage space, trailers having folding beds have been disclosed. For example, Burris, U.S. Pat. No. 4,239,258, Dec. 16, 1980; Spainhower, U.S. Pat. No. 7,540,528, Jun. 2, 2009; and Fahrbach, U.S. Pat. No. 7,891,697, Feb. 22, 2011, disclose folding flat bed trailers. The Spainhower trailer has a bed with two folding sections and has a tongue connected to the rear section. The Burris and Fahrbach trailers have beds with three folding sections and have a tongue connected to the middle section.

The bed of a flat bed trailer must be high enough above the ground to provide adequate clearance when the trailer is towed. Light weight cargo can be lifted up manually from the ground onto the bed, but other means must be used to load heavy wheeled cargo such as motorcycles, lawn tractors, and all terrain vehicles. A first method for loading is to employ a powered lifting device such as a fork lift truck. However, fork lift trucks are rarely available for personal use. A second method is to load and unload the trailer from an elevated platform such as a loading dock. Again, elevated platforms are rarely available for personal use. A third method for loading is to use a ramp consisting of long wood or metal planks between the bed and the ground. Ramps are prone to loss and must be secured onto the trailer during transport.

A fourth method for loading a trailer is to include a folding ramp as part of the bed of the trailer. For example, trailers with folding ramps that are part of the bed are disclosed in Law et al., U.S. Pat. No. 4,514,132, Apr. 30, 1985; and Thedford et al, U.S. Pat. No. 7,909,355, Mar. 22, 2011. The folding ramp is lowered to the ground for loading or unloading and is raised during transport.

A fifth method for loading a trailer is to lower and tilt the entire bed. For example, lowering and tilting trailers with airbag suspensions are disclosed by Nowell et al. and Fankhauser et al. as previously cited. Nowell et al. disclose a four-wheeled trailer having an airbag suspension on the rear pair of wheels that, when the airbags are deflated, allows the entire bed of the trailer to lower and tilt toward the rear. The entire bed thus forms a ramp upon which the cargo can be loaded. Fankhauser et al. disclose a two-wheeled trailer having an airbag suspension that, when the airbags are deflated, allows the entire bed of the trailer to lower.

Notwithstanding the many trailers that have been disclosed, there continues to be a demand for an improved folding bed trailer that tilts and lowers with a compact airbag suspension.

SUMMARY OF THE INVENTION

The general object of this invention is to provide an improved folding bed trailer that tilts and lowers with a compact airbag suspension.

I have invented an improved folding bed trailer. The trailer comprises: (a) a flat bed comprising: (i) a flat front section having a transverse front edge and a transverse rear edge; (ii) a flat middle section having a transverse front edge and a transverse rear edge; (iii) a flat rear section having a transverse front edge and a transverse rear edge; (iv) a first hinge connecting the rear edge of the front section and the front edge of the middle section, the first hinge having a 180 degree of travel such that the front section is foldable upon the middle section; and (v) a second hinge connecting the rear edge of the middle section and the front edge of the rear section, the second hinge having a 180 degree of travel such that the rear section is foldable upon the middle section; (b) a tongue having a forward end with a downwardly facing coupler for attachment to a towing vehicle and having an opposed end with a hinge connected to the front edge of the front section of the flat bed, the tongue hinge having a 180 degree of travel such that the tongue is foldable upon the front section with the coupler facing downwardly when the front section is folded upon the middle section; (c) a suspension system having two sides connected to the bed, each side of the suspension system comprising an outwardly extending axle; and (d) a wheel attached to the axle of each side of the suspension system.

I have also invented an improved tilting bed trailer having a compact airbag suspension. The trailer comprises: (a) a flat bed having a transverse front edge; (b) a tongue having a forward end with a downwardly facing coupler for attachment to a towing vehicle and having an opposed end connected to the front edge of the flat bed; (c) a suspension system having two sides connected to the bed with the two sides connected to each other by a cross member, each side of the suspension system comprising: (i) a platform rotatably attached to the bed with a rigid lever arm and a shock absorber; (ii) an inflatable/deflatable airbag positioned between the platform and the bed; (iii) a riser attached to the platform; and (iv) an outwardly extending axle attached to the riser, the axle defining a horizontal plane that is above the platform; such that the rigid lever arm forms a lever having at one end a pivoting point at the bed and having the airbag, riser, and axle at an opposite end, such that when the airbags are inflated the flat bed is above the horizontal plane defined by the axles and when the airbags are deflated the flat bed lowers and tilts with a portion of the flat bed below the horizontal plane defined by the axles; and (d) a wheel attached to the axle of each side of the suspension system.

The trailer of this invention tilts toward the rear with the entire bed forming a ramp for easy loading (and unloading) when the airbags are deflated. The trailer also folds for compact transport and for compact vertical storage. The trailer also has a compact airbag suspension system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a preferred embodiment of the trailer of this invention in an operating position.

FIG. 2 is a top plan view thereof.

FIG. 3 is a bottom plan view thereof.

FIG. 4 is a detail perspective view of the airbag suspension components thereof.

FIG. 5 is a side elevation view of the preferred embodiment of the trailer in the raised, operating position.

FIG. 6 is a side elevation view thereof in the lowered, tilted position for loading and unloading.

FIG. 7 is a side elevation view thereof showing a first folding step.

FIG. 8 is a side elevation view thereof showing a second folding step.

FIG. 9 is a side elevation view thereof showing a third folding step.

FIG. 10 is a side elevation view thereof showing a fourth folding step.

FIG. 11 is a side elevation view thereof showing the vertical folded storage position.

FIG. 12 is a left side perspective view of the right side first hinge in the folded storage position.

FIG. 13 is a rear elevation view thereof.

FIG. 14 is a right side elevation view thereof.

FIG. 15 is a top plan view of the right side hinge is the operating position.

FIG. 16 is a right side elevation view thereof.

FIG. 17 is a left side elevation view of the left side second hinge in the folded storage position.

FIG. 18 is a left side elevation view of the left side second hinge in the operating position.

DETAILED DESCRIPTION OF THE INVENTION

1. The Invention in General

This invention is best understood by reference to the drawings. Referring first to FIGS. 1 to 3, a preferred embodiment of the trailer 10 of this invention comprises a flat bed 20 with two sides, a tongue 30, a suspension system 40 with two sides, and a wheel 50 attached to each side of the suspension system. The components are discussed in more detail below.

2. The Flat Bed

The flat bed 20 comprises three sections—a front section 21, a middle section 22, and a rear section 23. The front section is connected to the middle section by a first hinge. The term “hinge” is used herein to refer to a single integral hinge (such as a piano hinge) and to multiple hinges that act along a common axis (such as door hinges). In the embodiment shown, the first hinge consists of two separate hinges—hinge 24R on the right side and hinge 24L the left side. The middle section is connected to the rear section by a second hinge. In the embodiment shown, the second hinge consists of two separate hinges—hinge 25R on the right side and hinge 25L the left side. The second hinge enables the rear section to fold upon the middle section. The first hinge enables the front section to fold upon the middle section and upon the folded rear section.

The three sections preferably have the same or similar dimensions so that the size of the bed in the folded position is minimized for a given unfolded size. For example, if the trailer has a length of nine feet (not including the tongue), the folded size is minimized if each section has a length of about three feet (one-third of nine feet). The trailer is generally about six to twelve feet in length (not including the tongue) and about three to six feet in width.

The trailer sections are made of a durable material such as metal, wood, or a combination of the two. The three sections of the preferred embodiment are made of wooden sheets lying within a metal frame 26. The three frames preferably include cross members 27 that provide additional strength. Each wooden sheet lies in a recess having a depth that is generally about three-fourths to one inch. This depth corresponds to the thickness of the wooden sheets so that the top of the wooden sheets are flush with the top of the metal frame. The interiors of the frames contain multiple support brackets 28 upon which the wooden sheets lie. Vertically oriented fasteners 29, such as screws, nuts and bolts, or the like, are used to attach the wooden sheets to the brackets.

In the preferred embodiment, the middle section contains two tabs 22 a projecting forward from its front edge and two tabs 22 b projecting rearwardly from its rear edge. The tabs are best seen in FIGS. 3, 12, and 15. The upper surfaces of the tabs are aligned with the lower surface of the sections. The front section and the rear section sit upon the tabs when the trailer is in the unfolded, operating position. The tabs thus help keep the sections of the trailers in a parallel position. In the preferred embodiment, the forward projecting tabs and the front section of the bed have aligned holes 22 c that accommodate nuts and bolts to secure the sections in the parallel, unfolded, operating position. The rearwardly projecting tabs and the rear section preferably have similar aligned holes.

In the preferred embodiment, the wooden bed of each section comprises a sheet of three-fourths to one inch thick plywood having a width of four feet and a length of about 31 and ⅞ inches. These dimensions enable the three bed sections to be cut from a single sheet of four by eight foot plywood with an allowance of one eighth inch for each kerf (width of the saw cut). Four by eight foot sheets of plywood are widely available in many different thicknesses and grades.

The hinges are shown in detail in FIGS. 12 to 18. The front section and the middle section are shown in phantom lines for illustration purposes. Referring first to FIG. 12, first hinge 24R on the right side is shown in the folded storage position. The hinge comprises two “L” shaped members, front member 24 a and rear member 24 b that pivot relative to each other about bolt 24 c. The front member and rear member have multiple beveled corners to allow them to pivot. The rear member has a block 24 d on its inner side against which the front member abuts when the trailer is in the unfolded, operating position. The block thus helps keep the sections of the trailers in a parallel position. The right side first hinge is shown in other views in the folded storage position in FIGS. 13 and 14. The right side first hinge is shown in the operating position in FIGS. 15 and 16. First hinge 24L on the left side is substantially a mirror image of hinge 24R on the right side.

Second hinge 25L is shown in detail in FIGS. 17 and 18. The second hinges are similar to the first hinges except that they pivot about slightly lower axes. The first hinges pivot about a higher axis than the second hinges to enable the front section to elevate sufficiently to fold upon both the middle section and the rear section. The right and left side second hinges are substantially mirror images of each other. The first and second hinges are attached to the sections of the bed by welding or with the use of fasteners.

3. The Tongue

The tongue 30 of the preferred embodiment contains two converging members 31 that are attached to the front edge of the front section of the flat bed at hinges 32. The two members converge at a downwardly-facing coupler 33 that attaches to a trailer hitch. A wide variety of couplers and hitches are well known in the art. For personal use, the most common hitch is the ball type. As explained in detail below, the tongue hinges preferably enable the tongue to pivot 180 degrees about a transverse horizontal axis. When the bed is fully folded, this pivoting places the coupler in a downward facing position that facilitates transportation while folded. If desired, the tongue contains a single member that is attached to a single hinge on the front edge of the first section of the flat bed.

4. The Suspension System and Wheels

An airbag suspension system 40 is connected to the middle section of the flat bed. The suspension system dampens movement when the airbags are inflated and enables the entire bed of the trailer to tilt when the airbags are deflated. As best seen in FIGS. 2 and 3, the preferred suspension system is completely behind the front edge of the middle section and completely forward of the rear edge of the middle section. The suspension system is thus completely within the length of the middle section and adds nothing to the height of the trailer when folded and stored in the vertical position. This structure enables the trailer to be folded compactly, as described in more detail below.

The suspension system has two sides, one located on each side of the trailer. The sides of the suspension system are substantially mirror images. For reasons explained below, each side of the suspension system is positioned on the middle section so that the rear of each wheel is in vertical alignment with the rear edge of the middle section when the trailer is in the operating (towing) position shown in FIG. 1.

Referring now to FIG. 4, each side of the suspension system contains a platform 41 that is rotatably attached to the middle section of the flat bed. The term “rotatably attached” means that the platform can rotate, or swivel, with respect to the middle section. The platforms are below (closer to the ground) than the axles. As explained in more detail below, this structure enables the entire bed to lower close to the ground when the airbags are deflated.

In the preferred embodiment, each platform is connected to the middle section by means of an inner shock absorber 42, an outer rigid lever arm 43, and an airbag 44. Each shock absorber further dampens movement of the bed during transport. Each shock absorber has an upper sleeve for attachment with a pin to the middle section and has a lower sleeve for attachment with a pin to the platform. The outer rigid lever arm has openings at its top for attachment of a pin to the middle section. It can be appreciated that the sides of the suspension systems pivot (rotate) about the pin attaching the top of the outer rigid arm to the bed. It can also be appreciated that the rigid lever arm has a pivoting point at the middle section of the bed at one end and has the airbag, riser, and axle at the opposite end

A cross member 45 preferably connects the platforms which, in turn, links the left side and right sides of the suspension system. Linking the left side and right side sides of the suspension system provides additional dampening.

Each airbag is sandwiched (mounted) between the middle section of the bed and each platform. In the preferred embodiment, a mounting bracket is attached to the underside of the middle section and the top of the airbag is attached to this mounting bracket. The airbag is conventional and can be inflated or deflated through valved air lines 70. Inflation can be accomplished by connection to an air compressor or other source of compressed air, such as a compressed air tank or canister. Deflation is accomplished by opening the valve in the air line and venting to the atmosphere.

A riser 46 is connected to the platform. The structure of the riser is a matter of choice. In the preferred embodiment, the riser is a section of square tube (also known as square channel). The riser is connected to and supports an outwardly extending non-rotating axle 47. The axle is connected to a spindle 48 having outwardly extending lug bolts. The spindle rotates freely on the axle and includes bearings or the like as desired to reduce friction between it and the axle. In the preferred embodiment, a fender support member 49 extends upwardly from the riser.

A wheel 50 is attached to each spindle by fastening lug nuts onto the lug bolts of the spindle. The wheels are conventional rubber tires on metal rims. As mentioned above, the wheels have a diameter such that their rearward surfaces are aligned with the rear edge of the middle section. In the preferred embodiment, a fender 60 is attached to the fender support member. The fenders contain upward splatter of water and dirt and thus help keep the top of the bed and the cargo clean.

It can be appreciated that this suspension system allows the platforms and wheels to move relative to the flat bed, which movement is dampened by the airbags and the shock absorbers. The amount of the dampening can be varied by adjusting the inflation of the airbags. The amount of the dampening can also be varied by adjusting the shock absorbers if they are of the adjustable type. It can also be appreciated that when the airbags are inflated the middle section of the flat bed is above the horizontal plane defined by the axles and when the airbags are deflated the flat bed lowers and tilts with the middle section of the flat bed below the horizontal plane defined by the axles

5. Optional Components

A variety of optional components are included with the trailer. One class of optional components are devices for inflating the airbags, such as air compressors and compressed air tanks or canisters. Another class of optional components are devices for securing cargo on the flat bed, such as chocks, tie-downs, poles, barriers, nets, fencing, and the like.

6. Uses

The trailer of this invention is used in the same manner as conventional flat bed trailers when in its unfolded, operating, towing position with both airbags inflated and with the bed in a substantially horizontal orientation as shown in FIG. 5. The vertical broken line A indicates that the rear edge of the second hinge and the rearward outer edges of the wheels are closely aligned in the same vertical plane. The horizontal broken line B indicates the horizontal plane defined by the axles. It can be seen that the platforms of the suspension system are below this horizontal plane. The wheel on the near side is omitted for illustration purposes in FIGS. 5 to 11.

Referring now to FIG. 6, the entire flat bed tilts to form a ramp when the airbags are deflated. The formation of a ramp eases loading and unloading and eliminates the need for separate ramps or for the use of a loading dock or a lifting device. The bed forms a relatively small angle to the horizontal that enables cargo having small ground clearances to be loaded and unloaded with ease.

As previously discussed, the trailer is foldable for compact transportation and for compact storage. The trailer is also conveniently folded for display at retail locations and when shipped (for example, from a point of manufacture to a point of sale). When the trailer is to be folded, the airbags can be inflated or deflated. The rear section is first folded over onto the middle section, as shown in FIGS. 7 and 8. The front section is then folded over onto the middle and rear sections, as shown in FIGS. 8, 9, and 13. The tongue is then pivoted 180 degrees about a transverse horizontal axis as shown in FIGS. 9 and 10. In this position, the trailer can be moved long distances by being pulled by a towing vehicle. The trailer can also be moved short distances by being pulled manually, either with or without the use of a dolly or trolley that engages the tongue.

For compact vertical storage, the entire folded assembly is rotated 90 degrees after folding so the trailer sections are vertical with the wheels positioned on the ground as shown in FIG. 11. It can be seen that the rear edge of the middle section and the bottom outer edges of the wheels are closely aligned in the same horizontal plane (the plane defined by the ground), thus enabling the folded trailer assembly to be stored in a stable, vertical position. It can also be seen that the overall height of the folded trailer assembly shown is equal to the length of the tongue. If the minimal overall height is desired, the length of the tongue is decreased to about the overall length of the three folding sections of the bed. As discussed above, this length is generally less than about three feet. The folded trailer assembly is easily moved as desired by rocking it back slightly to elevate the hinge off the ground so that only the wheels make contact with the ground. The folded trailer can thus be moved in its vertical position without the need for separate rollers, wheels, casters, or the like to ease movement. 

I claim:
 1. A folding bed trailer comprising: (a) a flat bed comprising: (i) a flat front section having a transverse front edge and a transverse rear edge; (ii) a flat middle section having a transverse front edge and a transverse rear edge; (iii) a flat rear section having a transverse front edge and a transverse rear edge; (iv) a first hinge connecting the rear edge of the front section and the front edge of the middle section, the first hinge having a 180 degree of travel such that the front section is foldable upon the middle section; and (v) a second hinge connecting the rear edge of the middle section and the front edge of the rear section, the second hinge having a 180 degree of travel such that the rear section is foldable upon the middle section; (b) a tongue having a forward end with a downwardly facing coupler for attachment to a towing vehicle and having an opposed end with a hinge connected to the front edge of the front section of the flat bed, the tongue hinge having a 180 degree of travel such that the tongue is foldable upon the front section with the coupler facing downwardly when the front section is folded upon the middle section; (c) a suspension system having two sides connected to the bed, each side of the suspension system comprising an outwardly extending axle; and (d) a wheel attached to the axle of each side of the suspension system.
 2. The folding bed trailer of claim 1 wherein the front section, the middle section, and the rear section of the bed are substantially the same size.
 3. The folding bed trailer of claim 2 wherein the flat bed sections comprise wooden sheets in metal frames. 